Fluid valve mechanisms utilize one or more fluid valve ports for the purpose of controlling flow of a fluid. The fluid valve mechanism includes a first valve body having a first port opening fluidically communicating with a first fluid transfer line (providing for either delivery or removal of the fluid), and further includes a second valve body having a second port opening fluidically communicating with a second fluid transfer line (providing the other of either delivery or removal of the fluid). A motive device (i.e., a motor or actuator) is provided to selectively move the first valve body with respect to the second valve body so as to thereby selectively align the first and second port openings and thereby regulate the fluidic communication therethrough, wherein the selectivity of the alignment ranges typically from a nonaligned state, wherein fluid flow through the first and second port openings is prevented, to a fully aligned state, wherein fluid flow through the first and second port openings is maximally unimpeded.
In order to prevent fluid leakage between the first and second valve bodies, a seal is provided, usually carried by the valve body connected to the fluid delivery line, wherein the seal circumscribes the valve opening thereat. Most commonly, a rubber O-ring is utilized for the seal, wherein the O-ring is seated in a seal channel formed in the valve body carrying the O-ring. Because the O-ring is compressed between a floor of the seal channel and the sidewall of the opposing valve body, a slidable seal is provided by the O-ring which prevents fluid leakage.
Referring now to FIG. 17, shown schematically is a fluid valve mechanism 10 having a conventional, prior art fluid valve port 12. A movable valve body, or “core”, 14, has formed therein a seal channel 16 into which is seated an O-ring 18, wherein the O-ring circumscribes a core port opening 20. A stationary valve body, or “manifold”, 22, has a manifold port opening 24. Now, referring additionally to FIG. 18, where the O-ring 18 spans the manifold port opening 24, the unsupported span 18′ of the O-ring tends to pop out from the seal channel 16, which tendency is exacerbated by stretching and compression forces being applied to the O-ring dynamically as the core rotates with respect to the manifold. This tendency of the O-ring to pop out of its seal channel can result in premature wear, cutting, jamming or otherwise a failure of the seal it provides. In general, for unsupported spans of the O-ring, problems of seating of the O-ring in its seal channel arise for unsupported span lengths exceeding about 3 diameters of the O-ring. A technique known in the prior art to prevent the O-ring from popping out via under cut walls of the seal channel. As seen by way of example in FIG. 19, the core 14′ has a seal channel 26 with undercut walls 28, whereby even though an unsupported span 18′″ of the O-ring 18″ exists, the O-ring is nonetheless trapped in the seal channel.
While undercut walls prevent the O-ring from popping out of its seal channel, the under cuts require expensive machining and are ordinarily fitted with custom O-rings, which are also expensive as compared with off-the-shelf, standard O-rings. Further, the problem of O-ring pop out from its seal channel is exacerbated by high frequency of opening/closing cycles, long term exposure to wide temperature fluctuations, and age related reduction in O-ring elasticity.
Accordingly, what remains needed in the art is to somehow provide a fluid valve port configured so as to allow a standard O-ring to be retained operably in its seal channel, with minimal wear and without cutting or jamming, wherein the seal channel is of a simple rectilinear shape.